A package of reforms aimed at cleaning up the system of MPs allowances is a missed opportunity, says a Kent MP.

Prime Minister Gordon Brown unexpectedly announced a series of proposed changes to the system of allowances on Tuesday. His proposals come amid continuing controversy over MPs expenses and follows a series of damaging stories involving his own ministers.

The proposals, which MPs could vote on next week, include the abolition of second homes allowances, worth up to £24,000 a year and their replacement with a flat rate attendance allowance.

Hugh Robertson (Con), Faversham and Mid Kent MP, described the reforms as a missed opportunity because the government had failed to incorporate any proposals to review the number of MPs needed at Westminster; changes to pensions and a reform of working hours that would avoid MPs having to work late into the night.

"Given that this is a ghastly mess, any attempt at reform has to be welcomed. But I would much rather the review had gone much further. It is a knee-jerk reaction because Gordon Brown has recognised that he has got a particular political problem. What is needed is a far more wide-ranging report that looks at the number of MPs we have; the whole question of the final salary scheme and how we employ and run our staff," he said.

The prospect of a flat rate allowance for attending Parliament has already provoked criticism, with both David Cameron and Nick Clegg saying it could be abused.

Mr Robertson said he shared some of the misgivings. "It is clearly not perfect but nobody has yet come up with a system that is."

There has been speculation that Mr Brown decided to act after being warned that the publication of detailed receipts for all MPs dating back several years was likely to lead to a further clutch of damaging stories in the media.