Motorists have been urged to curb their speed after the number of fines issued in Norfolk increased by more than a third in the month after proposals were announced to raise the maximum speed limit.

The government revealed in September that it planned to increase the national limit from 70mph to 80mph on motorways and some sections of dual carriageway under an initiative to boost the economy.

However, concerns have been raised about the road safety impact of speeding on the country's main roads, which could come into force by early 2013.

The warning comes after figures obtained by the Evening News under the Freedom of Information Act revealed that more than 1,500 additional speeding tickets were issued during a 30 day period this autumn compared to the same period last year.

However, officials from Norfolk Safety Camera Partnership denied that they were trying to profiteer from fixed and mobile cameras and that the increase in fines was unlikely to have been caused by the Department for Transport's announcement on the speed limit consultation.

Under figures obtained from Norfolk Police, 3,700 motorists were caught driving over the speed limit in Norfolk between September 29 and October 29, with 394 of those committed on the A11 and 295 on the A47.

For the same period in 2010, 2,178 drivers were caught speeding in the county. Of those, 114 were on the A11 and 163 on the A47. Monies from speeding fines are sent back to the Treasury.

Peter Anderson, safety camera manager for Norfolk and Suffolk, said there were many factors that influenced speeding figures such as roadworks and driving conditions.

'It is pure coincidence with the talk of raising the speed limit. The weather plays a part in controlling things and people slow down in poor weather. We try to spread enforcement out so that various areas get the right attention. Our aim is to get people to pay more notice to speed limits and our ultimate aim is to win people's hearts and minds about speeding,' he said.

Former transport secretary Philip Hammond announced at the end of September that the coalition government planned to launch a full consultation on changing the maximum speed limit for the first time since 1965, which would shorten journey times and benefit the economy.

However, Mr Anderson said there were concerns that the scheme could result in more deaths and serious injuries on Britain's motorways and dual carriageways.

'I have seen the views of the police liaison to the Department for Transport and there is real concern about going to 80mph on a dual carriageway. I think it is a way off yet if it happens at all. The majority of people do not have training to cope. Cars maybe able to cope driving those speeds but it is totally different to going 50 to 60mph,' he said.

A spokesman for the Department for Transport said the government had announced that there might be a case for increasing the maximum speed limit and the department would be consulting organisations in the near future.