It follows an investigation by The Detail which revealed that campaign spending in the last Northern Ireland Assembly election was much higher than previously believed or widely reported.

The Electoral Commission revealed in the summer that parties had spent a total of £150,080 in the March 2017 election campaign.

However, new figures compiled by The Detail show that the 90 elected candidates spent a further £407,611 during the same campaign, bringing the total campaign expenditure to over half a million pounds.

Ann Watt said: “Information about candidate spending is only available for public inspection by physically going into the electoral office to view the forms. Under current rules it’s not that easily accessible and ultimately we believe that information should be put online.

“On top of that we as the Electoral Commission have no role in looking at any issues relating to candidate spending, our role only relates to party spending. At the moment candidate spending allegations are a matter for the police, but we believe that we should also have a role in investigating allegations about candidate spending.

“That would require a change in the law.”