There are very few circumstances where halacha, as recorded in the S”A, permit kefia. All of the following have to have occurred for coercion to be halachicly permissible: 1) There had to have been a beis din trial with both spouses and the dayanim all present at the same time in beis din and 2) both spouses were given the opportunity to present their case in beis din and 3) the dayanim after hearing both sides determined that based on the circumstances halachic cause exists that obligates him to issue a divorce even if he wishes not to and 4) he refuses to issue the Get and 5) the dayanim further deliberate and rule that halacha permits kefia under the circumstances.
Even when he’s obligated under halacha to give a Get, halacha still says he cannot be physically coerced under most circumstances. (He’s a rasha if he doesn’t and beis din may be permitted to authorize lesser forms of pressure such as harchokos Rabbeinu Tam.) And halacha doesn’t even obligate a Get in the first place in most typical cases unless there is an unusual factor that Chazal specifically and explicitly say mandates a Get. Some of the few such scenarios that Chazal authorized it are a) an illegal marriage (i.e. Kohen and gerusha) b) he has a physical deformity or c) he engaged in physical violence against her, and was warned by beis din to stop but he continued after having been warned. (Shulchan Aruch says if he denies it then beis din needs witnesses testifying to it.) Shulchan Aruch lists various types of cases where a spouses request for a divorce is denied and the couple is told by beis din to go back to living together as husband and wife.