Liberal Vannin MHK Peter Karran has called for a Public Accounts Committee investigation into the upgrade of the Tetra emergency communications system.
Tynwald voted in November to approved spending just under £5m on a replacement system.
This was despite a letter being circulated just before the debate from a rival bidder that claimed it could have delivered the upgrade to Tetra at half the cost.
In his letter to PAC chairman Alfred Cannan MHK, Mr Karran said: ‘As a former member of the Department of Home Affairs I do feel there is a need for a full investigation into the procurement and value for money aspect as far as this issue is concerned.
‘I hope that the Public Accounts Committee will carry out a thorough investigation. The investigation should be carried out as to whether it was premature and whether a more effective way could have been employed to resolve the issue in order that the taxpayer has not been short changed by this issue just being “nodded through” by Tynwald.’
Tetra is used by the island’s emergency services, including the police, as well as Civil Defence personnel and marshals during the TT, Manx Grand Prix and Classic TT.
Home Affairs Minister Juan Watterson told Tynwald in November that the upgrade and replacement was needed as the system had reached the end of its life and maintenance and support contracts could not be extended.