UPDATED 2pm: Jockeying begins ahead of the government's spectrum auction.

The government has cut $12 million a year from its mobile phone bill after signing the three major players in a public sector-wide deal.

New shared account scheme could boost carrier's share of the lucrative contract market. A customer lobbyist says the gauntlet has been thrown down to other carriers.

System uses cellphones for tap-and-go payments with Wellington and Auckland buses, plus some taxis and retailers.

PLUS: Mobile market share | ISP market share.