The duo will be joined by Canterbury utility back Colin Slade to help in training with the All Blacks Tri-nations squad as it prepares to face the Springboks.
The All Blacks play the Springboks in Hamilton on September 12, and then play the Wallabies in Wellington on September 19.
Thomson and Donnelly have both been in good form for Otago and had fine games in the side's 29-7 win over Northland last Friday night.
For Donnelly, a lock, it is the second such camp he has been to, after going to Auckland last month to help out in training.
Thomson, a loose forward, was in the All Blacks at the start of the international season but broke a bone in his right hand in the opening test against France at Carisbrook on June 13, and has been out of the side since.
Thomson has been called in to provide cover in the loose forwards with Kieran Read recovering from a knock to the knee.
Donnelly is called in to help make up the numbers at locking time as Hawkes Bay lock Bryn Evans has had season-ending surgery on a damaged back.
Thomson's selection shows he is still in the All Black picture, and is reward for some excellent domestic form over the past couple of weeks.
Neither player is likely to make the All Black squad for the last two tests in Hamilton and Wellington.
Otago challenges for the Ranfurly Shield against Canterbury on the same day the All Blacks take on the Springboks in Hamilton.
Slade, who has impressed in the past couple of matches when playing fullback for Canterbury, has been called into the squad with injuries to centre Conrad Smith (centre), inside back Luke McAlister (cheekbone) and Tamati Ellison (calf).
The Otago Rugby Football Union is still waiting to hear whether it will host a test next year but there has been unconfirmed reports the All Blacks will play Wales on June 26 at Carisbrook, in the second test of a series.
Otago Rugby Football Union chief executive Richard Reid said he was still waiting to hear if Carisbrook would host a test.
If the new Forsyth Barr stadium is built on time, next year may be the last test held at Carisbrook.
