Fears of an economic meltdown in the UK in the case of a hung parliament have been dismissed by a leading credit rating agency and senior economists.

Analysis suggests that of the 16 countries worldwide that currently have the top AAA financial stability rating, 10 are run by coalition governments. The majority of nations that have taken the toughest action in recent decades to tackle their debts were also governed at the time by coalitions.

David Cameron and George Osborne, the shadow chancellor, have warned a hung parliament would spark a sterling crisis and the intervention of the International Monetary Fund, which is helping to bail out the beleaguered Greek economy.

But the Moody's ratings agency this weekend argued a plan agreed by a coalition would have broad public support and could make it easier to push through the spend­ing cuts essential to reducing the deficit.

Arnaud Mares, its lead UK analyst, said: "A hung parliament does not in itself have direct implications for Moody's UK rating. The three main parties broadly agree on the desirability of fiscal consolidation on a scale that, if implemented strictly over the course of the next parliament, would be consistent with the government maintaining its Moody's AAA rating."

Another ratings agency, Fitch, assessed Britain's prospects to be "stable", a view it said it had reached bearing in mind the possibility of a hung parliament.

The Standard and Poor's agency lowered its assessment to "negative" almost a year ago, when the Conservatives had a strong lead in the opinion polls.

Sixteen countries currently have an AAA rating – awarded to nations deemed to have close to zero risk of defaulting on their debts – from the main credit ratings agencies. Ten, including Germany, the Netherlands, New Zealand, Sweden and Switz­erland – have coalition governments and 12 use a form of proportional representation for elections.

History also suggests having large majorities in government does not prevent crises of sterling. The 1949 and 1967 devaluations took place when Labour had a clear majority. In 1985 sterling fell to just over $1 when Margaret Thatcher had a landslide majority and in 1992 the Tories had a working majority when Britain fell out of the Exchange Rate Mechanism.

In contrast, the last time there was cross-party co-operation in a hung parliament situation – the Lib-Lab pact of 1977/78 – it delivered lower inflation, lower unemployment and a recovery in the value of sterling, and the IMF was paid off from the 1976 crisis. The deal included painful cuts to public spending.

The House of Commons library also discovered seven of the toughest 10 "fiscal consolidations" – programmes of belt-tightening – in the western world since 1970 were undertaken by coalition administrations.

London's financial sector is becoming accustomed to the idea the election on 6 May will not deliver the decisive Conservative victory it might have wished for. Consequently investors have factored a hung parliament into their calculations.

Research consultants Capital Economics said in a briefing note to investment houses on Friday that markets were "becoming rather less fearful of the prospect of a hung parliament". It said it had warn­ed in February "some of the worst fears over a hung parliament might be overdone and there are signs that the markets are starting to come round to that view".

Jonathan Loynes, its chief Europe economist, said: "We are not suggesting that all worries about a hung parliament are completely misguided. We are at a precarious position and the finances are in a mess. Action must be taken to sort them out very quickly.

"But there is growing recognition among the parties that further action to address the fiscal problem is needed. The markets have taken heart from that in the past week."

Investment consultant Desmond O'Driscoll, of Lighthouse Financial Initiatives, said: "Whatever nasty medicine has got to be taken, it would be more acceptable coming from a consensus government."

James Caan, the entrepreneur who features in BBC2's Dragons Den, said: "The financial markets are anticipating a hung parliament, and it will come as no surprise to them. Now it is becoming increasingly likely they will be factoring this into their assess­ment of the economy and government borrowing."