Heat speed restrictions are gone from Auckland's Southern Line

Trains were required to slow to 40-kilometres-an-hour in sections between Otahuhu and Papakura stations.

It caused major cancellations a fortnight ago.

KiwiRail's Jon Knight says they've removed more than four kilometres of restrictions, and 500 metres of other temporary network speed limits.

He says a technical issue with signals in Britomart, which caused up to 40 minute delays last week, should be fixed by mid-March.

Auckland One Rail CEO, Martin Kearney, says they also hope to resolve crew shortages by then.