The south's rescue helicopters were sent out 21 times between Saturday morning and mid-afternoon on Monday, with jobs ranging from a double call-out to the Waipahi highway crash to a search and rescue on Stewart Island, according to the service's public mission log.

The Otago Southland Rescue Helicopter Trust publishes a running list of every mission, giving the time, a location and a broad category but no details about patients. It shows nine missions on Saturday, eight on Sunday and four by 2.45pm on Monday.

The most recent Southland entries are two logged at 12.59pm on Monday for Stewart Island/Rakiura, one classed as search and rescue and the other as an accident. No police statement about an incident on the island had been published by early Monday evening, and the log does not say what happened or whether anyone was hurt.

On Sunday a helicopter was sent to an accident in Fiordland National Park at 11.22am. Again, no further information has been made public.

Saturday's busiest stretch came just after midday, when two flights were logged to Waipahi at 12.26pm and 12.38pm. Police said two people were critically injured and three others hurt when a vehicle crashed on SH1 near Webb Road at about 12.05pm; St John said two patients were flown to Dunedin Hospital.

Most of the weekend's work was less dramatic. Fifteen of the 21 missions were hospital transfers, the flights that move patients between the region's smaller hospitals and the larger ones. Five were logged at Kew, the Invercargill suburb that is home to Southland Hospital, including one a couple of minutes after midnight on Saturday and another before 6am on Sunday. Two were logged at Gore, four at Oamaru and four at Frankton, where Queenstown's Lakes District Hospital sits. Frankton also had a transfer between facilities on Saturday morning.

Eight of the 21 entries carry the tag IFR, aviation shorthand for instrument flight rules, under which crews fly on instruments rather than by sight.

The log shows 53 missions for the first nine days of November. The quietest day was Sunday 1 November, with two, and the busiest were Thursday 5 November and Saturday, with nine each. Friday's four included an accident at Wairuna at 10.57am, two minutes after police say they were alerted to the fatal collision between a car and a tractor on SH1 northwest of Clinton.

The trust says the service runs three dedicated helicopters from its base at Taieri, near Dunedin, and two from Queenstown, and can call on Southern Lakes Helicopters for work in Fiordland when needed. Its fleet list includes Airbus H145 machines fitted with rescue winches.

The service operates around the clock every day of the year. The trust says it is only partly funded by the Government and depends on community donations for the rest.

In an emergency, call 111. The trust's mission log is updated at otagorescue.co.nz.